Maltese star thistle, or tocalote. Non-native, an invader from Europe. Found on top of Inspiration and on Jesusita, Tunnel and Rattlesnake trails.
First observed blooming in May. Still blooming in July. Lots of small (1/4 inch) yellow flowers on a plant about 1m high.
This looks very like yellow star thistle (C. solstitialis) save that the other has a flower which is about twice as big on a plant about twice as tall. (I didn’t realize we had two species until I saw them blooming side by side on Rattlesnake)